Most of WLAN devices are equipped with SMA-RP connectors, whilst outdoor antennas are equipped with N-type connectors. Using H-155 cable it is needed to end it with SMA RP connector on one side, e.g. E84565, and adequate male or female connector depending on the antenna on the other side. If we don't have crimper we should choose twist-on connector. However, crimp-on connectors are preferred for the reason of their reliability.

As a crimper for the H-155 cable, the E8000 or E80001 can be used. Besides a crimper, there will be also needed a soldering iron.

In the case of H-1000, which is a thicker cable than H-155, the SMA-RP connector should be used together with N connector (it is impossible to put SMA-RP connector directly on H-1000 cable). We recommend the ready-to-use connections/adapters E83220, E83225.

The role of connectors in WLAN systems

Objective data on quality of connectors can be provided only by specific measurements performed with the use of expensive devices. However, when buying a connector it is possible to estimate the quality of the thread, galvanic coating, etc.

The most visible fault of coaxial connectors is deflection of central tip/pin (so called - hot) from the the axis of symmetry. It is recommended to pay attention to the defect after the connector has been mounted on the cable. It happens that the dielectric becomes overheated during soldering, which causes deflection of the central pin from the axis of symmetry.

When connecting a plug which has a nut, it should be paid attention to screwing it to the socket using always and only the nut. Turning the connector itself, it causes central wire to scratch onto the hole surface, and may result in significant deterioration of parameters. We can also assert that even properly operated connectors keep their parameters only for limited number of cycles (connections and disconnections) - typically up to 500-800 cycles - however improper use significantly shortens their service life. Additionally, for the connectors mounted on cables, it is worth to know exact manufacturer recommendations. The manufacturer usually informs about proper distances of the layers of the cable that should be cut in relation to the "hot" wire tip.

Even best connector causes a loss of signal. So, one should avoid excessive connectors associated with antenna feeder. A good manufacturer of connectors shows two important parameters, specifying signal loss. The first of them - VSWR - specifies what part of signal's power is being reflected back to the transmitter. Typical value for 2.4 GHz band shouldn't exceed 1.5dB, which corresponds with reflection of ca. 4% of the signal's power. The second of them is called insertion loss, the value of which shouldn't be larger than 0.2dB, which corresponds to ca. 0.5% of the signal's power.

Connectors applied for antennas mounted outdoors should have adequate protection against water. It is a fundamental matter, because any drop of water which penetrates the line will cause that significant part of the transmitted power (even a few tens of percent) will be dissipated, i.e. turned into heat.

Generally, only N-type connectors meet the requirements for this kind of use - they have been designed for military marine applications. Unfortunately significant part of this type of connectors doesn't support the original norms. If the manufacturer doesn't inform that the connector is compliant to adequate seal or military norms like MIL-C-39012 (the products of renowned firms), it is recommended to pay attention to the rubber pad mounted between two metal washers. They are used to squeeze the isolator, to make it fit tight to housing walls and this way to block the access of water.
The rubber of which the isolator is made shouldn't be too hard. Unfortunately, it is impossible to estimate thread's tightness with a naked eye.

Improperly mounted connector may be the reason of large signal loss and problems with running the network. It is important to properly prepare the cable and mount the connectors. In the case of crimp-on connectors it is needed to pay attention on the size of crimping jaws, given by the manufacturer.

Clamp-on connectors, unlike crimp-on ones, are demountable, so the same connector can be mounted on a cable many times. Mounting clamp-on connectors may be difficult somewhat. Typical clamp-on connector consists of a pin, which is soldered to the central cable's wire, two pads, seal, sleeve clamping cable's shield to the connector, and a nut, which secures all elements.

Crimp-on connectors for H-155 cable. Proper performance of connectors influences quality of transmission link. During designing process of the antennas ATK-16 (A7124) and ATK-P1 (A7130), there were carried out tests with selection of different connectors; also the quality of work of different installers was tested. It turned out that in the case of coincidence of adverse factors related to bad quality of the connector and work, antenna's gain decreased even by 30%. Due to quality and repeatability, we have decided to use connectors manufactured by Unicon company, and the crimper E8000.

To show in detail where the problem is, we have reviewed 19 connectors and 3 crimping tools from our offer. Parameters of each connector have been measured - the results are collected in the table.

1. outer sleeve diameter
2. inner sleeve diameter
3. outer corps diameter
4. sleeve wall thickness
5. distance sleeve - corps; space for the braid

1. hexagon size declared by manufacturer (+/- 0.1 mm)
2. hexagon size - measured

Polish producer of connectors - Unicon maintains repeatable mechanical parameters, thicker sleeve lowers the risk of deformation after crimp-on. In the case when outer sleeve diameter is smaller, it is required to use crimper with smaller hexagon size. The tools used by us have this size within 6.4 - 6.5 mm. Manufacturer's tolerance is +/- 0.1 mm. The achieved results show that differences in connector sizes exist and they should be work in during assemblage, however practical experience from crimping suggests that very important thing is right crimping technique.

Basically, there can't be cut too much of outer coating, because sleeve crimped-on braid itself is less stable, it can't be allowed for braid or shield to stick out from the sleeve. To have connection maximally tight, if it is possible, a fragment of outer coating can be left under the sleeve. Besides, that braid and shield, on which the sleeve is about to lie, should be in the best possible condition; if it is crashed or to short, the connection won't be solid. Due to the width of crimper's jaw is less than the width of sleeve it is possible to crimp it twice - on both ends. If we use single crimp, the sleeve should be crimped maximally close to the connector - don't crimp it in the middle or nearby the cable - such connection won't be stable.

We have collected the ways of mounting most of RF connectors in 1.06 MB PDF file here (there is a lot of well-understandable figures in; several useful translations: lutowac = solder, zacisnac = crimp, wywinac oplot = turn up the braid, wcisnac pod oplot = press under the braid).

WLAN connectors